Accentuated Eccentric Training: Effects on Horizontal Jump Distance and Muscle Strength Among Young Adults

Research Article Open Access Accentuated eccentric training: effects on horizontal jump distance and muscle strength among young adults

Abstract Volume 3 Issue 3 - 2018

Accentuated eccentric loading is a training method in which greater load is applied during 1 1 eccentric phase in comparison to concentric phase of a coupled eccentric‒concentric action. Nizar Abdul Majeedkutty, Pang Shi Yiing, 2 The aim of this study was to evaluate the training effects of accentuated eccentric load Anila Paul countermovement jump on horizontal jump distance and muscle strength of lower extremity 1Department of Physiotherapy, University Tunku Abdul Rahman, among young adults. This study was designed as a randomized controlled trial with pretest Malaysia and post‒test model. The subjects were randomly categorized into a control group (n=15) 2Department of Physiotherapy, Medical Trust College of that underwent body‒mass countermovement jump and an intervention group (n=15) Physiotherapy, India submitted to Accentuated Eccentric Training. 30 subjects including 16 males and 14 females participated in the four‒week long training. Accentuated Eccentric Training group showed Correspondence: Nizar Abdul Majeedkutty, Department of significant improvement in horizontal jump distance and maximum muscle strength of lower Physiotherapy, University Tunku Abdul Rahman, Malaysia, Tel extremities. An increase in horizontal jump distance (+13.15%) and 5RM squat strength was 0060163702375, Email [email protected] noted (+23.14%) after four weeks of training. In conclusion, it would appear that Accentuated Eccentric Training enhance athletic performance in young adults. Application of accentuated Received: May 04, 2018 | Published: June 12, 2018 eccentric loading could be further investigated for its effects on agility and exercise induced muscle damage in athletes of different sports.

Keywords: accentuated eccentric loading, countermovement jump, horizontal jump distance, maximum muscle strength

Introduction comparison to concentric phase of a movement. It is hypothesized that a greater concentric force will be developed through higher loading in Efficient and effective training methods are continually sought eccentric action. It is believed that AEL involving coupled concentric after by physiotherapists, coaches, and athletes to enhance sports and overloaded eccentric muscle actions could optimize the effects 1 performance, Resisted movement training is used in athletic of stretch‒shortening cycle (SSC). An additional mechanical stimulus conditioning to enhance power and athletic performance by was given during eccentric phase in order to produce greater force executing a movement important to sport with added resistance that and power output during concentric phase in SSC activities. AEL is not excessive and does not adversely affect the movement pattern. augments the negative work of eccentric phase, thereby increasing Traditional weight training exercises performed slowly with heavy the positive work of concentric phase to overcome the negative work. resistance are well suited to enhance strength but may not be optimal Countermovement is described as a movement in a direction opposite for power development requiring higher velocity because there are to the goal direction. Some tasks such as throwing and jumping considerable portions of deceleration during the motion, whereas start with countermovement in order to improve performance. resisted movement training can allow for acceleration throughout Countermovement is commonly observed in actions involving SSC. 2 the range of motion. Eccentric exercises are frequently applied in The pre‒stretch in countermovement leads to higher speed and strength and conditioning program by giving external resistance to the greater force production in athletic performance. The spring‒like targeted muscles in the direction which is opposite the muscle pull. mechanism found in SSC actions,5 could be applied to explain the 3 According to, eccentric exercises improve maximal and explosive superior results gained in actions involving countermovement. The muscle strength, shift the optimal muscle length, improve muscle coil of spring immediately rebounds and jumps off the surface in an coordination and induce muscular adaptations. There are few different opposite direction after it is released from compression. The spring training modalities derived from eccentric exercises such as “pure jumps higher or farther by increasing the compression speed and eccentric” and “coupled eccentric‒concentric” manner. Accentuated compression force applied on the spring. This is known as the “rate eccentric loading (AEL) is one of the extended concepts from eccentric of loading”. Studies related to the acute and chronic effects brought exercises. Accentuated eccentric loading is a training method in by AEL were inconclusive, mostly due to differences in selecting which greater load is applied during eccentric phase in comparison to subjects, exercise, load prescription, and method of providing AEL.5 concentric phase of a coupled eccentric‒concentric action. The aim of some studies demonstrated that the AEL protocol could acutely this study was to evaluate the training effects of accentuated eccentric enhance athletic performance while some studies showed the contrary load countermovement jump on horizontal jump distance and results. Therefore, further research should be conducted to evaluate maximum muscle strength of lower extremity among young adults. the training effects of AEL among untrained subjects because training 4 According to, AEL was described as magnitude of eccentric load the untrained individual is the initial step of novice training programs. is higher than that of concentric load while maintaining the natural Moreover, there is lack of study conducted to investigate the effects mechanism of movements involving concentric and eccentric action. of AEL on standing long jump (broad jump) performance. Standing It means that an additional load is applied during eccentric phase in long jump is an athletic event and becomes one of the annual events

Submit Manuscript | http://medcraveonline.com MOJ Yoga Physical Ther. 2018;3(3):59‒62. 59 ©2018 Majeedkutty et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and build upon your work non-commercially. Copyright: Accentuated eccentric training: effects on horizontal jump distance and muscle strength among young 60 adults ©2018 Majeedkutty et al.

in Norwegian Championship since 1995. In addition, it is frequently Three attempts were allowed. It is a time and cost‒efficient method implemented in training regimen to improve athletic performance, without requiring any high‒technology equipment. Standing long especially lower body strength and explosive power. The authors from jump test could be used as a tool to measure lower limb power when a study suggested trainers should use long jump training instead of laboratory method is not feasible.8 conducted a study to investigate the vertical jump to improve swimming start performance. According to,6 feasibility of standing long jump test to assess the lower limb power sprinting speed in rugby could be enhanced by increasing lower body in elite sportsmen when the Wingate test is not practical to be applied strength. Some studies have demonstrated that standing long jump has and indicated that standing long jump test is a reliable and accurate strong correlation with sprinting by sharing common physiological method for the assessment. and biochemical determinants.7 Therefore, more studies related to improving jump performance are encouraged in order to benefit the 5‒repetition maximum strength test (5RM squat test) athletes who reach plateau stage of performance and athletes who 5RM Squat Test is proclaimed to be a reliable instrument to assess just recover from injury and wish to reach targeted performance muscular strength in recreational sports. Subjects had preparatory with minimizing injury risk in a short period. The aim of this study session with 20 repetitions of standing back extension exercise and was to evaluate the training effects of accentuated eccentric load 20 repetitions of squat without load. Before test session, the bar was countermovement jump on horizontal jump distance and maximum placed on the rack according to the height of subjects. Subjects were muscle strength of lower extremity among young adults. advised to wear tight weight belt to minimize the risk of injury. A pre‒ familiarization session without additional weight was scheduled prior Methods to actual test. Subjects were instructed to dismount the bar from the We adopted a randomized controlled trial design to determine rack, place on the back shoulder and stand in an upright position with the effects of accentuated eccentric training. Participants had been feet shoulder‒width apart. It was followed by squat until reaching categorized into intervention group (Accentuated Eccentric Jump) approximately 110° of knee flexion with greater trochanter of femur and control group (Body Mass Jump) using block randomization and superior border of patella were in same horizontal plane. Then, to ensure that roughly equal numbers of samples are randomly subjects ascend to original position according to verbal sign given assigned to the two groups in a way that both known and unknown by assessor. The load was increased with 5‒10kg for every trial until prognostic factors are balanced at the start of the trial. Randomization subjects was unable to lift the weight sixth repetition for the trial. was performed using computer‒generated random numbers. Thirty The 5‒RM strength test is a valid measurement method in recreational young adults (16 males, 14 females) were recruited among students sports with less physical stress and injury risk.9 of University Tunku Abdul Rahman (UTAR) Sungai Long Campus. Training protocol Subjects were screened for eligibility according to the inclusion and exclusion criteria. Subjects of either gender of age between 18‒23 Prior to training, general warming up session was conducted by years with Body Mass Index between 18.5 and 23 (According to subjects, including 10 minutes of cycling, approximately five minutes Asian Standard) were included in this trial. Physically healthy subjects of dynamic stretching (hip flexor, hip extensor, knee extensor, knee screened by Physical Activity Readiness Questionnaire (PAR‒Q) as flexor and ankle plantar flexor), 10minutes of dynamic activities well as untrained subjects; not trained in a particular skill for sports (three sets of one‒minute skips, two minutes of leg swings, two were eligible to participate in this trial. Subjects with spinal problems, minutes of arm swings) as well as 10 simple squats. After warming hypermobile, unstable and painful joints were excluded. The study up session, three to five minutes of resting time were given to subjects was conducted at UTAR Gymnasium. Subjects were excluded if before starting training session. The subjects in the accentuated there was any history of musculoskeletal injury in the last six months, eccentric training and normal strength training groups were tasked cardiovascular disease and congenital malformations. Participants with performing a 4‒week training program made up of 3 training were assigned randomly to two groups; either in control (BMJ) group sessions per week. A pre‒familiarization session was provided for or intervention (AEJ) group. All participants were informed about the standing long jump and squatting with barbell. The subjects in AEJ potential risks of the experiment and written informed consent was group held dumbbells in each hand during eccentric phase of the jump obtained from the participants prior to the trial. The experiments were and dropped the dumbbell before commencing the concentric phase performed in accordance with the ethical standards of the Helsinki of jump. AEJ group was advised to jump in a pattern as similar as Declaration. This study was approved by the Scientific and Ethical natural countermovement jump. Moore and Schilling proposed using Review Committee (SERC) of UTAR. The subjects were informed dumbbells and therabands to provide accentuated eccentric loading. about the scope and protocol of the trial, and that they are free to BMJ group was encouraged to use arm swing in the propulsive phase. withdraw from the trial at any point of time. The numbers of session and repetition were increased every week, as outlined in Table 1. Outcome measurements Table 1 Training volume of AEJ & BMJ groups Standing long jump test Week 1 Week 2 Week 3 Week 4 Exercise Standing long jump (SLJ) test is commonly used to measure the S&R S&R S&R S&R lower limb explosive power and general muscular fitness by determine AEJ 4x5 6x5 8x5 10x5 horizontal jump distance. The athlete was instructed to stand behind a line marked on the ground with feet slightly apart. A two foot take‒ BMJ 4x5 6x5 8x5 10x5 off and landing was used, with swinging of the arms and bending of the knees to provide forward drive. The subject attempts to jump S, Session; R, Repetition as far as possible, landing on both feet without falling backwards.

Citation: Majeedkutty NA, Yiing PS, Paul A. Accentuated eccentric training: effects on horizontal jump distance and muscle strength among young adults. MOJ Yoga Physical Ther. 2018;3(3):59‒62. DOI: 10.15406/mojypt.2018.03.00045 Copyright: Accentuated eccentric training: effects on horizontal jump distance and muscle strength among young 61 adults ©2018 Majeedkutty et al.

Statistical analyses and results to normal strength training when either isometric or eccentric strength are measured. The study revealed that by accentuating the eccentric Statistical analyses were performed by using SPSS statistical phase a ‘mean improvement’ of 85% was gained compared to that of package version 23. The data of horizontal jump distance collected concentric only training of 78%.11 Additional eccentric load promotes from SLJ test and maximum muscle strength of lower extremities greater number of motor units to be recruited and the elastic properties collected from 5RM squat test of both groups were statistically of muscle allow for a more powerful concentric contraction after a analyzed to compare the effects between AEJ and BMJ groups. The stretch associated with the eccentric contraction. During eccentric normality of collected data of SLJ test and 5RM squat test at pre‒test loading the agonist muscle can achieve an active state and force as and post‒test session for both groups were statistically determined a result of some cross bridges being attached prior the subsequent by Shapiro‒Wilk Test in order to be qualified for using parametric portion of an exercise.12 Another study conducted to compare the test. Paired‒Sample t test was used to compare pre‒test and post‒test strength and neuromuscular adaptations reported significantly greater mean of SLJ test and 5RM squat test within groups. Unpaired t test increases in concentric 1RM of the elbow extensors.13 A study was used to compare pre‒test and post‒test mean of SLJ test and 5RM published in mid‒2016 discovered that just five weeks of accentuated squat test between intervention group and control group. Descriptive eccentric loading training provided highly noticeable results, even statistics were done in the form of mean, standard deviation (SD). among experience resistance trainees. The findings of this study by a Table 2 outlined that pre‒test values of dependent variables were team of scientists from the Department of Biology of Physical Activity normally distributed according to Shapiro‒Wilk test. The p‒values at University of Jyvaskyla in Finland indicated visible improvement for all dependent variables were more than 0.05 which showed that it in their work capacity, resistance, muscle activation, force production was statistically insignificant for unequal distribution. Therefore, the and muscle cross‒sectional area.14 Additional eccentric load enhances parametric tests were suitable to analyze the data. Table 3 shows the eccentric impulse, the rate of force development and will result in mean difference ‒11.042 with standard deviation of 6.781 between increase in integrated electromyography across the eccentric phase. pre‒test and post‒test 5RM squat test and mean difference –O.185 The fact that the results were so visible even among experienced with standard deviation of 0.094 between pre‒test and post‒test SLJ strength trainees means that accelerated eccentric loading training in AEJ group that was statistically significant with p‒value of less than could be a good option for anyone to get over their plateau. This (p<0.05). AES group demonstrated statistically significant difference assumption has been proved by the findings of the current study in 5‒Repetition Maximum Strength Test and Standing Long Jump conducted among untrained young adults. Accelerated eccentric Test. loading training is basically the reverse of regular training. Instead of Table 2 Determining normality of dependent variables placing emphasis on the concentric (shortening) phase of the exercise, the emphasis is on the eccentric (lengthening) phase of the exercise. Group Mean±SD P value The greater external load is applied during the eccentric phase. In BMJ 1.529±0.312 0.209 addition, eccentric overload training showed superior results in the Pre SLJ (m) percentage of type IIA fibres expressing MHC IIx mRNA, in the AEJ 1.708±0.293 0.851 cross‒sectional area of type IIB fiber, in the level of mRNA of fast, BMJ 43.654±14.917 0.111 glycolytic fibres, and in the level of capillary lactate after exercises Pre 5RM (kg) as compared to traditional strength training.15 Post‒exercise lactate AEJ 47.708±8.425 0.266 clearance was found significantly greater in accentuated eccentric Table 3 Paired‒samples T test of pre‒test and post‒test of SLJ test and 5RM training compared to traditional strength training. This factor along in AEJ group with greater take‒off speed could yield greater jump distance could have acted in favor of subjects that underwent AEJ training to enhance Outcome Post Mean T P measure- Pre test their athletic performance. Previous studies have reported that drop test difference value value ments jumps result in exercise induced muscle damage, but the extent of this 16 1.893± ‒0.185± damage is reduced after subsequent bouts of drop jumps. Traditional SLJ (m) 1.708±0.293 ‒6.823* 0.001 0.270 0.094 training focuses primarily on the concentric phase of the workout. The 58.750± ‒11.042± eccentric phase is usually used to give the muscles a break between 5RM (kg) 47.708±8.425 ‒5.641* 0.001 8.758 6.781 exertions, but according to the research, it could be the best time to push the muscle harder. Paying more attention to muscles during the *Paired‒Samples T Test was performed, level of significance p<0.05 eccentric phase of any exercise is a good way to essentially access 17,18 Discussion untapped strength. This study evaluated the effects of six week accentuated eccentric Conclusion load countermovement jump training on horizontal jump distance Implementing Accentuated Eccentric Loading training to and maximum muscle strength of lower extremities among young strengthening has shown to bring out gains in horizontal jump adults. The AEJ protocol was developed with the suggested potential distance and maximum muscle strength of lower extremity among physiological mechanisms (neural stimulation, stretching of parallel young adults. This is a fantastic nugget of knowledge for all athletes. and series muscle‒tendon complex, elasticity of tendon, pre‒tension In conclusion, this study has shown that jump performance and as well as effects of PAP) as mentioned in the introduction. This muscle strength can be enhanced by accentuated eccentric muscle study followed the progression of training as mentioned in the study 10 action when compared with a traditional protocol. This may provide conducted by. The results of the current study are in accordance with a more practical method for coaches to enhance short‒term explosive the findings reported by previous studies on Accentuated eccentric movements in athletic populations. training. Accentuated eccentric training seems to be routinely superior

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